Conventional flexible packages generally include external or integrated sliding means or other similar devices designed to allow a user to selectively gain access into the pouch or package. Traditionally, non-integrated, twist ties and other tying means have also been used to close an open-end portion of a flexible package. These devices often require the manufacturing of additional and often costly materials and/or devices into the packages.
Due to the problems associated with external closure devices for packages, the industry has developed integrated closeable devices. U.S. Pat. Nos. 4,913,561, 5,692,837, and 6,186,663 disclose such packaging. Current typical reclosable devices, most commonly known as zippers, tend to be pre-made at separate manufacturing sites and then shipped to the site where the actual package is manufactured. The reclosable device is then introduced into the packaging machinery and typically heat sealed into or onto the package. These reclosable devices usually are comprised of two pieces that have been mated together by male and female interlocking members. The mating process is usually performed by either pinching the two interlocking members together (press-to-close mechanism) or sliding a mechanism (zipper mechanism) along the top of the reclosable device, which causes the two interlocking members to be interlocked.
These press-to-close closure mechanisms are sometimes difficult to align when attempting to mate together, often causing a failure of a true closure. Furthermore, when a packager is filling the package through the press-to-close closure mechanism, and when the consumer is pouring the contents out of the package, small pieces of the product can get caught in tracks of the mating interlocking members, causing a breach across the interlocking components and hampering any positive seal. The compromise of the integrity of the seal between the mating locking components may also be caused by localized crushing (e.g., proximate side seal) of the interlocking members during manufacturing, shipping, handling, and use by the consumer. The localized crushing need only be enough to plastically deform either of the interlocking members to cause a leak.
Further, most zipper-type closure mechanisms merely serve to close off the top portion of the package by pulling or forcing together the top portions of the front and back panels of the package. This zipper-type closure mechanism has two significant drawbacks. First, it reduces the internal holding volume of the package since, in a closed position, side gussets of the package are forced to contact at an end proximate the access opening. Second, a space or gap can remain when the zipper-type closure mechanism is in its closed position. The gap permits air to flow in and out of the package. Although the zipper-type closures may be easier for some consumers to operate, and may have a more positive closure with respect to the press-to-close closure mechanism, they can be expensive and, like the press to close closure mechanisms, often do not create an ideal barrier after the package has been opened by the consumer for the first time.
Some designs of the zipper and press-to-close mechanisms are suitable for maintaining a water or liquid tight seal. However, the interlocking members of both the zipper and the press-to-close closure mechanisms may also allow for fluid leakage and they may undergo plastic deformation after repeated use that adversely affects the ability of the mechanism to seal fluids. Moreover, the zipper and press-to-close mechanisms may not be suitable for a gas tight seal. Accordingly, the contents of the package are susceptible to oxidation and other air-borne problems, such as the release of odors.
As a result, there is a need for a flexible package that substantially solves the above-referenced problems with conventional package designs, configurations, and manufacturing methods.